'\" te
.\"  Copyright (c) 2004, Sun Microsystems, Inc.  All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
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.TH DDI_STRTOUL 9F "May 13, 2004"
.SH NAME
ddi_strtoul \- String conversion functions
.SH SYNOPSIS
.nf
#include <sys/ddi.h>
#include <sys/sunddi.h>

\fBint\fR \fBddi_strtoul\fR(\fBconst char *\fR\fIstr\fR, \fBchar **\fR\fIendptr\fR, \fBint\fR \fIbase\fR,
     \fBunsigned long *\fR\fIresult\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI)
.SH PARAMETERS
.ne 2
.na
\fB\fIstr\fR \fR
.ad
.RS 11n
Pointer to a character string to be converted.
.RE

.sp
.ne 2
.na
\fB\fIendptr\fR \fR
.ad
.RS 11n
Post-conversion final string of unrecognized characters.
.RE

.sp
.ne 2
.na
\fB\fIbase\fR\fR
.ad
.RS 11n
Radix used for conversion.
.RE

.sp
.ne 2
.na
\fB\fIresult\fR \fR
.ad
.RS 11n
Pointer to variable which contains the converted value.
.RE

.SH DESCRIPTION
The \fBddi_strtoul()\fR function converts the initial portion of the string
pointed to by \fIstr\fR to a type \fBunsigned long\fR int representation and
stores the converted value in \fIresult\fR.
.sp
.LP
The  function first decomposes the input string into three parts:
.RS +4
.TP
1.
An initial (possibly empty) sequence of white-space characters
(' ', '\et', '\en', '\er', '\ef')
.RE
.RS +4
.TP
2.
A subject sequence interpreted as an integer represented in some radix
determined by the value of \fIbase\fR
.RE
.RS +4
.TP
3.
A final  string of one or more unrecognized characters, including the
terminating null byte of the input string.
.RE
.sp
.LP
The \fBddi_strtoul()\fR function then attempts to convert the subject sequence
to an \fBunsigned\fR integer and returns the result.
.sp
.LP
If the value of \fIbase\fR is 0, the expected form of the  subject sequence is
that of a decimal constant, octal constant or hexadecimal constant, any of
which may be preceded by a plus ("+") or minus ("-") sign. A decimal constant
begins with a non-zero digit, and consists of a sequence of decimal digits. An
octal constant consists  of  the prefix 0 optionally followed by a sequence of
the digits 0 to 7 only. A hexadecimal  constant consists of the prefix 0x or 0X
followed by a sequence of the decimal digits and letters a (or A) to f (or F)
with values 10 to 15 respectively.
.sp
.LP
If the value of \fIbase\fR is between 2 and 36, the expected form of  the
subject sequence is a sequence of letters and digits representing an integer
with the radix specified by \fIbase\fR, optionally preceded by a plus or minus
sign. The letters from a (or A) to z (or Z) inclusive are ascribed the values
10 to 35 and only letters whose ascribed values are less than that of
\fIbase\fR are permitted. If the value of \fIbase\fR is 16, the characters 0x
or 0X may optionally precede the sequence of letters and digits, following the
sign if present.
.sp
.LP
The subject sequence is defined  as the longest initial subsequence of the
input string, starting with the first non-white-space character that is of the
expected form. The subject sequence contains no characters if the input string
is empty or consists entirely of white-space characters, or if the first
non-white-space character is other than a sign or a permissible letter or
digit.
.sp
.LP
If the subject sequence has the expected form and the  value of \fIbase\fR is
0, the sequence of characters starting with the first digit is interpreted as
an integer constant. If the subject sequence has the expected form and the
value of \fIbase\fR is between 2 and 36, it is used as the \fIbase\fR for
conversion, ascribing  to each letter its value as given above. If the subject
sequence begins with a minus sign, the value resulting from the conversion is
negated. A pointer to the final string is stored in the object pointed to by
\fIendptr\fR, provided that \fIendptr\fR is not a null pointer.
.sp
.LP
If the subject sequence is empty or does not have the expected  form, no
conversion is performed and the value of \fIstr\fR is stored in the object
pointed to by \fIendptr\fR, provided that \fIendptr\fR is not a null pointer.
.SH RETURN VALUES
Upon successful completion, \fBddi_strtoul()\fR returns \fB0\fR and stores the
converted value in \fIresult\fR. If no conversion is performed due to invalid
\fIbase\fR, \fBddi_strtoul()\fR returns \fBEINVAL\fR and the variable pointed
by \fIresult\fR is not changed.
.sp
.LP
If the correct value is outside the range  of representable values,
\fBddi_strtoul()\fR returns \fBERANGE\fR and the value pointed to by
\fIresult\fR is not changed.
.SH CONTEXT
The \fBddi_strtoul()\fR function may be called from user, kernel or interrupt
context.
.SH SEE ALSO
\fIWriting Device Drivers\fR
